CN114231839A - Mining anchor rod steel suitable for deep processing of 500MPa level and production method - Google Patents
Mining anchor rod steel suitable for deep processing of 500MPa level and production method Download PDFInfo
- Publication number
- CN114231839A CN114231839A CN202111393893.7A CN202111393893A CN114231839A CN 114231839 A CN114231839 A CN 114231839A CN 202111393893 A CN202111393893 A CN 202111393893A CN 114231839 A CN114231839 A CN 114231839A
- Authority
- CN
- China
- Prior art keywords
- steel
- content
- percent
- controlled
- anchor rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0025—Adding carbon material
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The invention belongs to the technical field of steel production, and particularly relates to mining anchor rod steel suitable for deep processing of 500MPa and a production method thereof, wherein the mining anchor rod steel comprises the following components in percentage by mass: 0.19 to 0.23 percent of C, 1.45 to 1.53 percent of Mn, 0.40 to 0.50 percent of Si, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, 0.06 to 0.07 percent of V, 180ppm of N and 180ppm of N, and the balance of Fe. The production method comprises the following steps: adding the raw materials into molten steel according to the weight percentage, smelting by a converter, refining by blowing argon from the bottom of a ladle, refining by an LF furnace to prepare qualified molten steel, pouring the molten steel through a continuous casting process to form a casting blank, and rolling the casting blank through a rolling process to prepare the anchor rod reinforcing steel bar with qualified performance. C in the steel is controlled to be 0.19-0.23%, V is controlled to be 0.06-0.07%, and N is controlled to be 180ppm, so that the solid solution precipitation of vanadium and nitrogen in the heating and rolling process is promoted, the effect of refining grains is achieved, the strength of 500MPa is stably guaranteed, the deep processing performance of the anchor rod steel is stable, and the brittle failure rate is zero.
Description
Technical Field
The invention belongs to the technical field of steel production, and particularly relates to mining anchor rod steel suitable for deep processing of 500MPa and a production method.
Background
In the prior art, the mining anchor rod steel is mainly used for supporting a coal roadway, and with the continuous increase of the mining depth of coal, the section size of the roadway is gradually enlarged, so that the pressure borne by the roadway support is increased, and the problem of coal mining safety production guarantee is more and more prominent, so that coal enterprises have increasingly strict requirements on the strength and deep processing performance of the mining anchor rod. The anchor rod steel deep processing means that anchor rod steel bars are subjected to necking, thread rolling and nut screwing processing to form a mining anchor rod steel product meeting the coal roadway support purpose. At present, the anchor rod steel bar is subjected to necking and thread rolling processing and then is subjected to tensile test, the problem that the tensile strength is unstable and is easy to break exists, the tensile strength of steel after deep processing corresponds to a tensile force range of 180 plus 220KN, the brittle failure occurrence rate is 38.46%, and adverse effects are caused on the safe use of the anchor rod steel in a coal roadway. The 500 MPa-level mining anchor rod steel produced by the conventional process has a wide control range of chemical components, the content of carbon (C) is less than or equal to 0.30 percent, the content of vanadium (V) is less than or equal to 0.08 percent, and the content of nitrogen (N) is 100 plus materials 220ppm, although the original material performance of the anchor rod steel in the component range can meet the national standard, the intensity fluctuation range of the anchor rod steel prepared into a coal roadway support product by deep processing is too large, and the problems that the performance of part of deep-processed products is low and the anchor rod steel is easy to break after deep processing exist.
Disclosure of Invention
In order to solve the technical problems, the invention provides mining anchor rod steel suitable for deep processing of 500MPa and a production method thereof, the narrow-interval precise control of the contents of carbon, nitrogen and vanadium in the steel is realized in the smelting process, the mechanical property of the anchor rod steel after being deep processed into a coal roadway support product is further improved on the basis of meeting the national standard of the performance of the original material of the anchor rod steel product, the stable standard of tensile strength is realized, and the brittle failure occurrence rate is zero.
The invention is realized in such a way, and provides mining anchor rod steel suitable for deep processing of 500MPa, which comprises the following components in percentage by mass: 0.19 to 0.23 percent of C, 1.45 to 1.53 percent of Mn, 0.40 to 0.50 percent of Si, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, 0.06 to 0.07 percent of V, 180ppm of N and 180ppm of N, and the balance of Fe.
Preferably, the composition comprises the following components in percentage by mass: 0.205% of C, 1.45% of Mn, 0.44% of Si, 0.030% of P, 0.014% of S, 0.061% of V, 152ppm of N and the balance Fe.
Further preferably, the coating comprises the following components in percentage by mass: 0.197 percent of C, 1.45 percent of Mn, 0.40 percent of Si, 0.028 percent of P, 0.023 percent of S, 0.062 percent of V, 165ppm percent of N and the balance of Fe.
Further preferably, the coating comprises the following components in percentage by mass: 0.21% of C, 1.46% of Mn, 0.47% of Si, 0.024% of P, 0.022% of S, 0.06% of V, 173ppm of N and the balance of Fe.
The invention also provides a production method of the mining anchor rod steel suitable for deep processing of 500MPa level, which comprises the following steps of adding raw materials into molten steel according to mass percent, smelting the raw materials in a converter, refining the molten steel by blowing argon from the bottom of a steel ladle, refining the molten steel in an LF furnace to prepare qualified molten steel, pouring the molten steel in a continuous casting process to form a casting blank, and rolling the casting blank in a rolling process to prepare the anchor rod steel with qualified performance, wherein the production method specifically comprises the following steps:
1) weighing raw materials according to mass percentage, adding the raw materials into molten steel in the converter tapping process, and filling the molten steel into a steel ladle, wherein slag discharging and rephosphorization are avoided in the tapping process; controlling the end point carbon of the converter to be between 0.07 and 0.1 percent, controlling the tapping temperature to be between 1670 and 1700 ℃, controlling the content of P in steel to be within 0.035 percent, and controlling the content of V in steel to be between 0.06 and 0.07 percent;
2) horizontally moving the ladle filled with the molten steel in the step 1) to a ladle bottom blowing argon gas refining by using a steel car, and carrying out deoxidation operation on the molten steel, wherein the content of O in the steel is controlled within 40ppm, the content of C in the steel is controlled between 0.19 and 0.23 percent, the content of Mn in the steel is controlled between 1.45 and 1.53 percent, and the content of Si in the steel is controlled between 0.40 and 0.50 percent;
3) hoisting the molten steel treated in the step 2) to an LF furnace by using a crown block for refining, and performing component fine adjustment, molten steel desulfurization and steel slag deoxidation operations on the molten steel, wherein the S content in the steel is controlled within 0.035%, and the TFe + MnO content in the slag is controlled within 1%;
4) hoisting the molten steel treated in the step 3) to a continuous casting process by using a crown block for pouring, casting the molten steel into a steel billet, controlling the temperature of a tundish between 1520 and 1540 ℃, controlling the superheat degree between 15 and 35 ℃, controlling the pulling speed between 2.2 and 2.5m/min, and controlling the N content of a casting blank between 120 and 180 ppm;
5) and (3) rolling the continuous casting slab obtained in the step 4) to prepare the deep-processed 500 MPa-level mining anchor rod steel with stable performance.
Preferably, the carbon content is controlled by the following specific method:
step 1) in the production process of a converter, molten iron with the sulfur content of less than or equal to 0.06% is used, a bottom blowing mode of 80% nitrogen and 20% argon is adopted, the bottom blowing flow in the early stage of converter blowing is controlled according to 15-20N.m3/h, and the bottom blowing flow in the later stage of converter blowing is controlled according to 20-30N.m3/h, so that the purpose of optimizing the bottom blowing process is achieved, the unevenness of components and temperature in a molten pool is effectively improved, the carbon content at the end point is controlled between 0.07-0.1% through high carbon drawing operation in the converter process, the blowing supplementing times are reduced, the TFe content in the end point slag sample is reduced, the carbon content is more than or equal to 96%, the nitrogen content is less than or equal to 0.03% and 180-230kg of micro-nitrogen carburant is added in the tapping process, and the primary qualified rate of the carbon content in steel is ensured;
and 3) adding 90-110kg of micro-nitrogen carburant with the carbon content of more than or equal to 96% and the nitrogen content of less than or equal to 0.03% in the LF furnace refining process to finely adjust the carbon content in the steel, so that the carbon content in the steel is controlled within the range of 0.19-0.23%.
Further preferably, the nitrogen content is controlled by the following specific method:
in the refining process of the step 1) of the converter, the step 2) and the step 3), 90-110kg of micro-nitrogen carburant with carbon content more than or equal to 96% and nitrogen content less than or equal to 0.03% is used, so that the nitrogen content of the raw material is reduced and the molten steel is excessively subjected to nitrogen increase, the control precision of the carbon content is improved, unnecessary carburant is reduced, and the nitrogen increase is controlled; during the refining operation of the LF furnace, the furnace cover falls to the lower limit, the micro-positive pressure operation is ensured, during the refining process, bottom blowing of large argon is forbidden for stirring, the argon flow rate during the temperature rising operation cannot exceed 300NL/min, the slag layer thickness is larger than 80mm, and the submerged arc operation in the whole process is realized;
in the step 4), the continuous casting ladle adopts a long nozzle for protection pouring, the thickness of a covering agent slag layer of the tundish is more than 50mm, air is isolated, the number of times of nozzle replacement of the tundish is reduced, secondary oxidation of molten steel caused when the molten steel flows into the tundish is avoided, nitrogen increase of the molten steel is prevented, and the nitrogen content in the steel is controlled within the range of 120 plus 180 ppm.
Further preferably, the specific method for controlling the vanadium content is as follows:
in the step 1), reasonable deoxidation alloying addition time and sequence are formulated, alloy is added when 1/4 steel is tapped, calcium silico-aluminum is added for deoxidation, the addition amount is determined according to the end-point oxygen content, then 2800kg of silicon-manganese alloy and 350kg of silicon-iron alloy are added, and finally 130kg of vanadium-nitrogen alloy is added for full pre-deoxidation, so that the recovery rate of V in the steel is ensured to be more than or equal to 95%.
Further preferably, the control of the content of phosphorus and sulfur is carried out by the following specific method:
in the step 1), 4-5 tons of lime is added in a converter process during smelting, 1-2 tons of sinter ore or pellet ore are added, the CaO content in slag, the iron oxide content in slag and the slag quantity are improved, the dephosphorization reaction is favorably carried out, the dephosphorization effect is stable, the end point alkalinity of a steel converter is ensured to be controlled to be 2.8-3.2, the converter process adopts sliding plate slag stopping, the steel tapping operators are required to strictly execute the process requirements, the tilting speed and the tilting angle of the converter are well controlled, the converter rapidly passes through a front slag discharging area and a rear slag discharging area in the steel tapping process, the steel tapping with slag is eliminated, and the phosphorus return quantity of molten steel is controlled to be less than or equal to 0.005%;
and 3) in the LF furnace refining process, the slag alkalinity is controlled to be more than or equal to 3.0 at the initial stage, and the TFe + MnO content in the slag is controlled to be less than or equal to 1%, so that the impurity adsorption capacity of the slag is improved, the molten steel deoxidation effect is improved, and the requirement of low sulfur content of the product is met.
Compared with the prior art, the invention has the advantages that:
by accurately controlling the narrow composition interval of C, N, P, S, V content in steel, particularly the accurate control of N content, effective nitrogen control measures are implemented in the links of converter, refining and continuous casting, so that the N content in the steel is controlled to be 120 plus 180ppm, the solid solution precipitation of vanadium nitrogen in the heating and rolling processes is effectively promoted, the refined crystal grains are achieved, the strength is improved, various performance indexes of the anchor rod steel stably meet the standard requirements, the brittle failure problem caused by steel deep processing due to higher nitrogen content is avoided, and the deep processing performance of the anchor rod steel is obviously improved. The anchor rod steel produced by the method has various performance indexes stably meeting the standard requirements, the deep processing performance is obviously improved, and the qualification rate of the deep processing is improved to 100 percent from 61.54 percent before improvement. The anchor rod steel has stable deep processing performance and zero brittle failure rate. The safety of the roadway support of the anchor rod steel coal roadway support product produced by the process is reliably guaranteed.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the invention, the final performance of the anchor rod steel is improved mainly by controlling the contents of carbon, nitrogen, vanadium, phosphorus and sulfur, and the concrete steps are as follows:
narrow composition control of carbon: carbon has the greatest influence on the yield strength and the tensile strength of steel, is the most effective strengthening element and the chemical element with the lowest cost, but has higher carbon content and can cause adverse influence on the toughness and the welding performance of steel. According to production and detection data, the carbon content is lower than 0.19%, the yield strength of steel is relatively low, and the average value of the yield strength of the detected steel is 495 MPa. The carbon content is higher than 0.23%, the elongation of the steel is low, and the average elongation after fracture of the detected steel is 18, so that the carbon content in the steel is controlled to be in the range of 0.19-0.23%.
And (3) controlling nitrogen: nitrogen precipitates V (C, N) nail-rolling austenite-ferrite grain boundaries in steel, promotes the formation of intragranular ferrite, improves the austenite-ferrite transformation ratio and refines the ferrite structure. In vanadium-containing steel, nitrogen can promote V (C, N) to be separated out, the structure of the steel is refined, the comprehensive performance of the steel is improved, surface high-nitrogen steel is researched, 70% of vanadium is separated out in a V (C, N) form, and only 20% of vanadium is dissolved in a matrix in a solid solution mode. Compared with low-nitrogen steel, the high-nitrogen steel has larger density of precipitated phases due to larger precipitation chemical driving force. Vanadium should be precipitated as much as possible while vanadium in solid solution is minimized to exert the precipitation strengthening effect of vanadium as much as possible. The nitrogen content is higher, which can cause the aging of the steel, reduce the plasticity and the toughness of the steel and have adverse effect on the deep processing performance of the steel. According to production and detection data, the nitrogen content is lower than 120ppm, the steel has the problem of low tensile strength, and the average value of the tensile strength of the detected steel is 638 MPa. The nitrogen content is higher than 180ppm, and the steel is easy to be brittle after deep processing, so the nitrogen content in the steel is controlled within the range of 120-180 ppm.
Controlling the content of vanadium: vanadium mainly influences the structure and the performance of steel by forming carbonitride, vanadium can promote the formation of pearlite and can thin ferrite laths, and vanadium carbide can precipitate in the ferrite laths in the pearlite, so that the precipitation strengthening effect of vanadium is fully utilized, and the hardness and the strength of steel are improved. In order to improve the strength and toughness of the anchor rod steel, the performance margin is fully considered, and the vanadium content in the steel is controlled within the range of 0.06-0.07 percent. According to production and detection data, the vanadium content is lower than 0.06 percent, the steel has the problem of low impact toughness, and the average value of the impact energy of the detected steel is 38KV2and/J. The vanadium content is higher than 0.07 percent, the steel hardness is higher, and the control of the steel-making cost is not facilitated, so the vanadium content in the steel is controlled within the range of 0.06-0.07 percent.
Phosphorus and sulfur control: phosphorus and sulfur are harmful elements in steel, and the plasticity, weldability and impact toughness of the steel are reduced when the content of phosphorus is too high. Phosphorus is easy to segregate in grain boundaries, so that the steel is cold-brittle, and the low-temperature impact toughness of the steel is obviously reduced. Sulfur can cause the steel to "hot shortness," which can reduce the toughness and strength of the steel. The phosphorus content is higher than 0.035%, the steel can generate P segregation and reduce the toughness, the sulfur content is higher than 0.035%, the steel can generate S segregation and generate 'hot brittleness', so the phosphorus and sulfur content in the steel is controlled within 0.035%.
Examples 1,
The mining anchor rod steel suitable for deep processing of 500MPa is prepared from the following chemical components in percentage by mass: 0.205% of C, 1.45% of Mn, 0.44% of Si, 0.030% of P, 0.014% of S, 0.061% of V, 152ppm of N and the balance Fe.
The production method suitable for deep processing of 500 MPa-level mining anchor rod steel comprises the following steps:
step 1: according to the chemical composition, the raw materials are weighed according to the mass percentage and added into molten steel in the converter tapping process, the molten steel is filled into a steel ladle, and slag discharging and rephosphorization are avoided in the tapping process.
And (3) converter process control: the end point C content is 0.08 percent, the tapping temperature is 1675 ℃, the P content in steel is 0.03 percent, and the V content in steel is 0.061 percent.
Step 2: and (3) horizontally moving the ladle filled with the molten steel in the step (1) to the ladle bottom for argon blowing refining by using a steel car, and deoxidizing the molten steel.
Controlling a ladle bottom argon blowing process: the O content in the steel is 33ppm, the C content in the steel is 0.205 percent, the Mn content in the steel is 1.45 percent, and the Si content in the steel is 0.44 percent.
And step 3: and (3) hoisting the molten steel treated in the step (2) to an LF furnace by using a crown block for refining, and performing component fine adjustment, molten steel desulfurization treatment and steel slag deoxidation on the molten steel.
Controlling a refining process: the S content in the discharged slag is 0.014%, and the TFe + MnO content in the slag is 0.07%.
And 4, step 4: and (4) hoisting the molten steel treated in the step (3) to a continuous casting process by using a crown block for pouring, and casting the molten steel into a billet.
Controlling a continuous casting process: the temperature of the continuous casting tundish is controlled to be 1522 and 1532 ℃, the superheat degree is controlled to be 17-30 ℃, the drawing speed is controlled to be 2.5m/min, and the N content of the casting blank is 152 ppm.
And 5: and (4) rolling the continuous casting slab obtained in the step (4) to prepare the deep-processed 500 MPa-level mining anchor rod reinforcing steel bar with stable performance.
The carbon content is controlled by the following specific method:
in the production process of a converter, molten iron with the sulfur content of less than or equal to 0.06 percent is used, a bottom blowing mode of 80 percent nitrogen and 20 percent argon is adopted, the bottom blowing flow in the early stage of converter blowing is controlled according to 15-20N.m3/h, and the bottom blowing flow in the later stage of converter blowing is controlled according to 20-30N.m3/h, so that the aim of optimizing the bottom blowing process is fulfilled, the unevenness of the components and the temperature in a molten pool is effectively improved, the carbon content at the end point is controlled between 0.07-0.1 percent through high carbon drawing operation in the converter process, the blowing supplementing times are reduced, the TFe content in the end point slag sample is reduced, the carbon content is more than or equal to 96 percent, the nitrogen content is less than or equal to 0.03 percent, 180-grade 230kg of micro-nitrogen carburant is added in the tapping process, and the primary qualified rate of the carbon content in steel is ensured;
and 3, adding 90-110kg of micro-nitrogen carburant with the carbon content of more than or equal to 96 percent and the nitrogen content of less than or equal to 0.03 percent in the refining process of the LF furnace to finely adjust the carbon content in the steel, so that the carbon content in the steel is controlled within the range of 0.19-0.23 percent.
The nitrogen content is controlled by the following specific method:
in the refining process of the converter in the step 1 and the refining process in the steps 2 and 3, 90-110kg of micro-nitrogen carburant with carbon content more than or equal to 96% and nitrogen content less than or equal to 0.03% is used, so that the nitrogen content of raw materials is reduced and the molten steel is excessively subjected to nitrogen increase, the carbon content control precision is improved, unnecessary carburant addition is reduced, and the nitrogen increase is controlled; during the refining operation of the LF furnace, the furnace cover falls to the lower limit, the micro-positive pressure operation is ensured, during the refining process, bottom blowing of large argon is forbidden for stirring, the argon flow rate during the temperature rising operation cannot exceed 300NL/min, the slag layer thickness is larger than 80mm, and the submerged arc operation in the whole process is realized;
in the step 4, the continuous casting ladle adopts a long nozzle for protection pouring, the thickness of a covering agent slag layer of the tundish is more than 50mm, air is isolated, the number of times of nozzle changing of the tundish is reduced, secondary oxidation of molten steel when the molten steel flows into the tundish is avoided, nitrogen increase of the molten steel is prevented, and the nitrogen content in the steel is controlled within the range of 120 plus 180 ppm.
The specific method for controlling the vanadium content is as follows:
in the step 1, reasonable deoxidation alloying addition time and sequence are formulated, alloy is added when 1/4 steel is tapped, calcium silico-aluminum is added for deoxidation, the addition amount is determined according to the end-point oxygen content, 2800kg of silicon-manganese alloy and 350kg of silicon-iron 200 and finally 130kg of vanadium-nitrogen alloy are added for full pre-deoxidation, and the recovery rate of V in steel is ensured to be more than or equal to 95%.
The specific method for controlling the contents of phosphorus and sulfur comprises the following steps:
in the step 1, in the converter process, 4-5 tons of lime is added during smelting, 1-2 tons of sinter ore or pellet ore are added, the CaO content in slag, the iron oxide content in slag and the slag quantity are improved, the dephosphorization reaction is favorably carried out, the dephosphorization effect is favorably stabilized, the end point alkalinity of the steel converter is ensured to be controlled to be 2.8-3.2, the converter process adopts sliding plate slag stopping, the steel tapping operators are required to strictly execute the process requirements, the tilting speed and the tilting angle of the converter are well controlled, the steel passes through a front slag discharging area and a rear slag discharging area quickly in the steel tapping process, the steel tapping with slag is eliminated, and the phosphorus return quantity of molten steel is controlled to be less than or equal to 0.005%;
in the step 3, in the LF furnace refining process, the slag alkalinity is controlled to be more than or equal to 3.0 at the initial stage, and the TFe + MnO content in the slag is controlled to be less than or equal to 1%, so that the impurity adsorption capacity of the slag is improved, the molten steel deoxidation effect is improved, and the requirement of low sulfur content of the product is met.
Examples 2,
The mining anchor rod steel suitable for deep processing of 500MPa is prepared from the following chemical components in percentage by mass: 0.197 percent of C, 1.45 percent of Mn, 0.40 percent of Si, 0.028 percent of P, 0.023 percent of S, 0.062 percent of V, 165ppm percent of N and the balance of Fe.
A production method suitable for deep processing of 500 MPa-level mining anchor rod steel comprises the following steps:
step 1: according to the chemical composition, the raw materials are weighed according to the mass percentage and added into molten steel in the converter tapping process, the molten steel is filled into a steel ladle, and slag discharging and rephosphorization are avoided in the tapping process.
And (3) converter process control: the end point C content is 0.1 percent, the tapping temperature is 1670 ℃, the P content in steel is 0.028 percent, and the V content in steel is 0.062 percent.
Step 2: and (3) horizontally moving the ladle filled with the molten steel in the step (1) to the ladle bottom for argon blowing refining by using a steel car, and deoxidizing the molten steel.
Controlling a ladle bottom argon blowing process: the O content in the steel is 40ppm, the C content in the steel is 0.197%, the Mn content in the steel is 1.45%, and the Si content in the steel is 0.40%.
And step 3: and (3) hoisting the molten steel treated in the step (2) to an LF furnace by using a crown block for refining, and performing component fine adjustment, molten steel desulfurization treatment and steel slag deoxidation on the molten steel.
Controlling a refining process: the content of S in the product is 0.023%, and the content of TFe and MnO in the slag is 0.09%.
And 4, step 4: and (4) hoisting the molten steel treated in the step (3) to a continuous casting process by using a crown block for pouring, and casting the molten steel into a billet.
Controlling a continuous casting process: the temperature of the continuous casting ladle is controlled to 1520 DEG and 1530 ℃, the superheat degree is controlled to be 15-25 ℃, the pulling speed is controlled to be 2.4m/min, and the N content of the casting blank is 165 ppm.
And 5: and (4) rolling the continuous casting slab obtained in the step (4) to prepare the deep-processed 500 MPa-level mining anchor rod reinforcing steel bar with stable performance.
The control of the carbon, nitrogen, vanadium, phosphorus, sulfur contents was the same as in example 1.
Examples 3,
The mining anchor rod steel suitable for deep processing of 500MPa is prepared from the following chemical components in percentage by mass: 0.21% of C, 1.46% of Mn, 0.47% of Si, 0.024% of P, 0.022% of S, 0.06% of V, 173ppm of N and the balance of Fe.
A production method suitable for deep processing of 500 MPa-level mining anchor rod steel comprises the following steps:
step 1: according to the chemical composition, the raw materials are weighed according to the mass percentage and added into molten steel in the converter tapping process, the molten steel is filled into a steel ladle, and slag discharging and rephosphorization are avoided in the tapping process.
And (3) converter process control: the end point C content is 0.07%, the tapping temperature is 1679 ℃, the P content in steel is 0.02%, and the V content in steel is 0.060%.
Step 2: and (3) horizontally moving the ladle filled with the molten steel in the step (1) to the ladle bottom for argon blowing refining by using a steel car, and deoxidizing the molten steel.
Controlling a ladle bottom argon blowing process: the O content in the steel is 43ppm, the C content in the steel is 0.210%, the Mn content in the steel is 1.46%, and the Si content in the steel is 0.47%.
And step 3: and (3) hoisting the molten steel treated in the step (2) to an LF furnace by using a crown block for refining, and performing component fine adjustment, molten steel desulfurization treatment and steel slag deoxidation on the molten steel.
Controlling a refining process: the S content of the product out of the station is 0.022%, and the TFe + MnO content of the slag is 0.07%.
And 4, step 4: and (4) hoisting the molten steel treated in the step (3) to a continuous casting process by using a crown block for pouring, and casting the molten steel into a billet.
Controlling a continuous casting process: the temperature of the continuous casting tundish is controlled to be 1523 and 1537 ℃, the superheat degree is controlled to be 18-32 ℃, the drawing speed is controlled to be 2.4m/min, and the N content of the casting blank is 173 ppm.
And 5: and (4) rolling the continuous casting slab obtained in the step (4) to prepare the deep-processed 500 MPa-level mining anchor rod reinforcing steel bar with stable performance.
The control of the carbon, nitrogen, vanadium, phosphorus, sulfur contents was the same as in example 1.
Examples of experiments,
The properties of the deep-processed 500 MPa-grade mining anchor rod steel obtained by applying the embodiments 1 to 3 to actual production are shown in the following table 1:
table 1:
the table shows that all properties of the deeply processed 500MPa grade mining anchor rod steel obtained by adopting the three schemes of the embodiment 1, the embodiment 2 and the embodiment 3 meet the requirements of supporting and using a coal roadway.
MG500 composition control before modification is as in table 2:
table 2:
before improvement (product in table 2), the performance indexes of the MG500 anchor rod steel are shown in table 3:
table 3:
as shown in the table 2 and the table 3, the corresponding properties of the components of the MG500 anchor rod steel before improvement have the problems of unqualified tensile strength, yield strength and elongation, part of the steel is lower than the standard requirement, wherein 6-10 parts of the steel do not need to be subjected to deep processing tensile test because the tensile strength and the yield strength of the parent metal do not meet the standard requirement, 1-5 parts of the steel are also lower than the standard requirement in deep processing performance, the brittle failure incidence rate is controlled to be between 32.55-42.78%, and the support safety of the coal roadway is seriously influenced.
The foregoing description is only exemplary of the invention and is not intended to limit the spirit of the invention.
Claims (9)
1. The mining anchor rod steel suitable for deep processing of 500MPa is characterized by comprising the following components in percentage by mass: 0.19 to 0.23 percent of C, 1.45 to 1.53 percent of Mn, 0.40 to 0.50 percent of Si, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, 0.06 to 0.07 percent of V, 180ppm of N and 180ppm of N, and the balance of Fe.
2. The mining anchor rod steel suitable for deep processing of 500MPa level according to claim 1 is characterized by comprising the following components in percentage by mass: 0.205% of C, 1.45% of Mn, 0.44% of Si, 0.030% of P, 0.014% of S, 0.061% of V, 152ppm of N and the balance Fe.
3. The mining anchor rod steel suitable for deep processing of 500MPa level according to claim 1 is characterized by comprising the following components in percentage by mass: 0.197 percent of C, 1.45 percent of Mn, 0.40 percent of Si, 0.028 percent of P, 0.023 percent of S, 0.062 percent of V, 165ppm percent of N and the balance of Fe.
4. The mining anchor rod steel suitable for deep processing of 500MPa level according to claim 1 is characterized by comprising the following components in percentage by mass: 0.21% of C, 1.46% of Mn, 0.47% of Si, 0.024% of P, 0.022% of S, 0.06% of V, 173ppm of N and the balance of Fe.
5. The production method of the mining anchor rod steel suitable for the deep processing of 500MPa level as claimed in claim 1, 2, 3 or 4, is characterized in that raw materials are added into molten steel according to mass percentage and are subjected to converter smelting, ladle bottom argon blowing refining and LF furnace refining to prepare qualified molten steel, the molten steel is cast through a continuous casting process to form a casting blank, and the casting blank is rolled through a rolling process to prepare the anchor rod steel with qualified performance, and the production method specifically comprises the following steps:
1) weighing raw materials according to mass percentage, adding the raw materials into molten steel in the converter tapping process, and filling the molten steel into a steel ladle, wherein slag discharging and rephosphorization are avoided in the tapping process; controlling the end point carbon of the converter to be between 0.07 and 0.1 percent, controlling the tapping temperature to be between 1670 and 1700 ℃, controlling the content of P in steel to be within 0.035 percent, and controlling the content of V in steel to be between 0.06 and 0.07 percent;
2) horizontally moving the ladle filled with the molten steel in the step 1) to a ladle bottom blowing argon gas refining by using a steel car, and carrying out deoxidation operation on the molten steel, wherein the content of O in the steel is controlled within 40ppm, the content of C in the steel is controlled between 0.19 and 0.23 percent, the content of Mn in the steel is controlled between 1.45 and 1.53 percent, and the content of Si in the steel is controlled between 0.40 and 0.50 percent;
3) hoisting the molten steel treated in the step 2) to an LF furnace by using a crown block for refining, and performing component fine adjustment, molten steel desulfurization and steel slag deoxidation operations on the molten steel, wherein the S content in the steel is controlled within 0.035%, and the TFe + MnO content in the slag is controlled within 1%;
4) hoisting the molten steel treated in the step 3) to a continuous casting process by using a crown block for pouring, casting the molten steel into a steel billet, controlling the temperature of a tundish between 1520 and 1540 ℃, controlling the superheat degree between 15 and 35 ℃, controlling the pulling speed between 2.2 and 2.5m/min, and controlling the N content of a casting blank between 120 and 180 ppm;
5) and (3) rolling the continuous casting slab obtained in the step 4) to prepare the deep-processed 500 MPa-level mining anchor rod steel with stable performance.
6. The production method suitable for deep processing of 500MPa grade mining anchor rod steel according to claim 5, is characterized in that the carbon content is controlled by the following specific method:
step 1) in the production process of a converter, molten iron with the sulfur content of less than or equal to 0.06% is used, a bottom blowing mode of 80% nitrogen and 20% argon is adopted, the bottom blowing flow in the early stage of converter blowing is controlled according to 15-20N.m3/h, and the bottom blowing flow in the later stage of converter blowing is controlled according to 20-30N.m3/h, so that the purpose of optimizing the bottom blowing process is achieved, the unevenness of components and temperature in a molten pool is effectively improved, the carbon content at the end point is controlled between 0.07-0.1% through high carbon drawing operation in the converter process, the blowing supplementing times are reduced, the TFe content in the end point slag sample is reduced, the carbon content is more than or equal to 96%, the nitrogen content is less than or equal to 0.03% and 180-230kg of micro-nitrogen carburant is added in the tapping process, and the primary qualified rate of the carbon content in steel is ensured;
and 3) adding 90-110kg of micro-nitrogen carburant with the carbon content of more than or equal to 96% and the nitrogen content of less than or equal to 0.03% in the LF furnace refining process to finely adjust the carbon content in the steel, so that the carbon content in the steel is controlled within the range of 0.19-0.23%.
7. The production method suitable for deep processing of 500MPa grade mining anchor rod steel according to claim 5, is characterized in that the nitrogen content is controlled by the following specific method:
in the refining process of the step 1) of the converter, the step 2) and the step 3), 90-110kg of micro-nitrogen carburant with carbon content more than or equal to 96% and nitrogen content less than or equal to 0.03% is used, so that the nitrogen content of the raw material is reduced and the molten steel is excessively subjected to nitrogen increase, the control precision of the carbon content is improved, unnecessary carburant is reduced, and the nitrogen increase is controlled; during the refining operation of the LF furnace, the furnace cover falls to the lower limit, the micro-positive pressure operation is ensured, during the refining process, bottom blowing of large argon is forbidden for stirring, the argon flow rate during the temperature rising operation cannot exceed 300NL/min, the slag layer thickness is larger than 80mm, and the submerged arc operation in the whole process is realized;
in the step 4), the continuous casting ladle adopts a long nozzle for protection pouring, the thickness of a covering agent slag layer of the tundish is more than 50mm, air is isolated, the number of times of nozzle replacement of the tundish is reduced, secondary oxidation of molten steel caused when the molten steel flows into the tundish is avoided, nitrogen increase of the molten steel is prevented, and the nitrogen content in the steel is controlled within the range of 120 plus 180 ppm.
8. The production method suitable for deep processing of 500MPa grade mining anchor rod steel according to claim 5, is characterized in that the control of vanadium content is as follows:
in the step 1), reasonable deoxidation alloying addition time and sequence are formulated, alloy is added when 1/4 steel is tapped, calcium silico-aluminum is added for deoxidation, the addition amount is determined according to the end-point oxygen content, then 2800kg of silicon-manganese alloy and 350kg of silicon-iron alloy are added, and finally 130kg of vanadium-nitrogen alloy is added for full pre-deoxidation, so that the recovery rate of V in the steel is ensured to be more than or equal to 95%.
9. The production method suitable for deep processing of 500MPa grade mining anchor rod steel according to claim 5, is characterized in that the control of the contents of phosphorus and sulfur is as follows:
in the step 1), 4-5 tons of lime is added in a converter process during smelting, 1-2 tons of sinter ore or pellet ore are added, the CaO content in slag, the iron oxide content in slag and the slag quantity are improved, the dephosphorization reaction is favorably carried out, the dephosphorization effect is stable, the end point alkalinity of a steel converter is ensured to be controlled to be 2.8-3.2, the converter process adopts sliding plate slag stopping, the steel tapping operators are required to strictly execute the process requirements, the tilting speed and the tilting angle of the converter are well controlled, the converter rapidly passes through a front slag discharging area and a rear slag discharging area in the steel tapping process, the steel tapping with slag is eliminated, and the phosphorus return quantity of molten steel is controlled to be less than or equal to 0.005%;
and 3) in the LF furnace refining process, the slag alkalinity is controlled to be more than or equal to 3.0 at the initial stage, and the TFe + MnO content in the slag is controlled to be less than or equal to 1%, so that the impurity adsorption capacity of the slag is improved, the molten steel deoxidation effect is improved, and the requirement of low sulfur content of the product is met.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111393893.7A CN114231839B (en) | 2021-11-23 | 2021-11-23 | Mining anchor rod steel suitable for deep processing of 500MPa and production method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111393893.7A CN114231839B (en) | 2021-11-23 | 2021-11-23 | Mining anchor rod steel suitable for deep processing of 500MPa and production method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114231839A true CN114231839A (en) | 2022-03-25 |
| CN114231839B CN114231839B (en) | 2023-06-06 |
Family
ID=80750591
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111393893.7A Active CN114231839B (en) | 2021-11-23 | 2021-11-23 | Mining anchor rod steel suitable for deep processing of 500MPa and production method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114231839B (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5100613A (en) * | 1990-10-16 | 1992-03-31 | Bethlehem Steel Co. | Hot-rolled microalloyed steel and its use in variable-thickness sections |
| JPH04157117A (en) * | 1990-10-20 | 1992-05-29 | Nippon Steel Corp | Production of rolled shape steel having excellent toughness of base metal and weld zone |
| CN102383033A (en) * | 2011-11-08 | 2012-03-21 | 河北钢铁股份有限公司承德分公司 | 600-MPa grade vanadium-containing high-strength hot-rolled steel bar and production method thereof |
| CN102899558A (en) * | 2012-11-16 | 2013-01-30 | 内蒙古包钢钢联股份有限公司 | 500Mpa-grade building aseismic reinforcement |
| CN103469117A (en) * | 2013-08-12 | 2013-12-25 | 武汉钢铁(集团)公司 | Hot-rolled ribbed steel bar having strength-to-yield ratio of 1.25 or more, and production method thereof |
| CN103898403A (en) * | 2014-04-09 | 2014-07-02 | 武汉钢铁(集团)公司 | HRB500 hot-rolled belt rib antiseismic steel bar and preparation method thereof |
| CN104451443A (en) * | 2014-11-21 | 2015-03-25 | 芜湖新兴铸管有限责任公司 | Anchor rod steel for coal mines and production method thereof |
| CN105908091A (en) * | 2016-04-29 | 2016-08-31 | 河北钢铁股份有限公司承德分公司 | Hot rolled reinforced bar for high-impact-toughness 500-MPa anchor rod and production method |
| WO2019100881A1 (en) * | 2017-11-24 | 2019-05-31 | 南京钢铁股份有限公司 | Continuous casting production method for square billets of vanadium-containing nitrogen-containing micro-alloyed peritectic steel |
| CN111286674A (en) * | 2020-03-31 | 2020-06-16 | 湖南华菱湘潭钢铁有限公司 | Production method of high-strength anchor rod reinforcing steel bar |
-
2021
- 2021-11-23 CN CN202111393893.7A patent/CN114231839B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5100613A (en) * | 1990-10-16 | 1992-03-31 | Bethlehem Steel Co. | Hot-rolled microalloyed steel and its use in variable-thickness sections |
| JPH04157117A (en) * | 1990-10-20 | 1992-05-29 | Nippon Steel Corp | Production of rolled shape steel having excellent toughness of base metal and weld zone |
| CN102383033A (en) * | 2011-11-08 | 2012-03-21 | 河北钢铁股份有限公司承德分公司 | 600-MPa grade vanadium-containing high-strength hot-rolled steel bar and production method thereof |
| CN102899558A (en) * | 2012-11-16 | 2013-01-30 | 内蒙古包钢钢联股份有限公司 | 500Mpa-grade building aseismic reinforcement |
| CN103469117A (en) * | 2013-08-12 | 2013-12-25 | 武汉钢铁(集团)公司 | Hot-rolled ribbed steel bar having strength-to-yield ratio of 1.25 or more, and production method thereof |
| CN103898403A (en) * | 2014-04-09 | 2014-07-02 | 武汉钢铁(集团)公司 | HRB500 hot-rolled belt rib antiseismic steel bar and preparation method thereof |
| CN104451443A (en) * | 2014-11-21 | 2015-03-25 | 芜湖新兴铸管有限责任公司 | Anchor rod steel for coal mines and production method thereof |
| CN105908091A (en) * | 2016-04-29 | 2016-08-31 | 河北钢铁股份有限公司承德分公司 | Hot rolled reinforced bar for high-impact-toughness 500-MPa anchor rod and production method |
| WO2019100881A1 (en) * | 2017-11-24 | 2019-05-31 | 南京钢铁股份有限公司 | Continuous casting production method for square billets of vanadium-containing nitrogen-containing micro-alloyed peritectic steel |
| CN111286674A (en) * | 2020-03-31 | 2020-06-16 | 湖南华菱湘潭钢铁有限公司 | Production method of high-strength anchor rod reinforcing steel bar |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114231839B (en) | 2023-06-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101550475B (en) | Method for producing ultra-low-carbon steel | |
| KR20130025383A (en) | Method for controlling titanium content in ultra-low carbon killed steel | |
| CN108823346B (en) | method for producing secondary flaw detection Q345R medium steel plate with low cost | |
| CN108568503B (en) | Method for accurately controlling carbon content of molten steel in 600MPa dual-phase steel tundish | |
| CN108893682B (en) | Die steel billet and preparation method thereof | |
| CN107354269A (en) | The method that RH complex deoxidizations produce ultra-low-carbon steel | |
| CN112708720A (en) | Smelting method for improving niobium yield of low-carbon low-silicon niobium-containing steel | |
| CN114606357A (en) | Method for removing phosphorus and leaving carbon in medium-high carbon steel by converter | |
| CN114480987A (en) | Rare earth-containing NM600 wear-resistant steel plate and preparation method thereof | |
| CN107974528B (en) | Method for reducing nitrogen content of molten steel at converter end point | |
| CN111020096B (en) | Single LF (low frequency) process low-nitrogen control method for dual-phase automobile steel DP590 | |
| CN114231839B (en) | Mining anchor rod steel suitable for deep processing of 500MPa and production method | |
| CN111926137B (en) | Preparation method for producing ship plate by adopting high-phosphorus, high-arsenic and high-sulfur molten iron | |
| CN113201683A (en) | Method for producing casting blank for HRB400E anti-seismic steel bar by adding high-vanadium pig iron into vanadium-titanium molten iron | |
| CN113005353A (en) | Method for improving flaw detection qualification rate of 14-30 mm Q345C steel plate | |
| CN111254247A (en) | Method for controlling titanium-containing IF steel continuous casting nozzle nodulation | |
| CN117604194B (en) | Vacuum consumable electrode for 300M steel and Al-free deoxidizing refining method thereof | |
| KR101412554B1 (en) | Manufacturing method of ultra-low carbon steel | |
| CN114381661B (en) | EH 36-grade steel plate and preparation method thereof | |
| CN111910116B (en) | Molybdenum-containing stainless steel smelting method for inhibiting molybdenum oxide volatilization and sputtering | |
| CN111334639B (en) | Method for promoting vanadium extraction and carbon conservation by using CO | |
| CN115747621B (en) | Ultralow titanium smelting method for high-aluminum or high-silicon electrical steel | |
| CN113789425B (en) | Method for smelting return high silicon steel water by converter | |
| CN113930682A (en) | Method for reducing production cost of anti-seismic reinforcing steel bar | |
| CN116426714A (en) | Production method of high-temperature low-phosphorus acid-resistant pipeline steel smelted by converter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |